Thread-cutter for sewing-machines



I. R. MUFFAU AND R. s. KELso.

.THREAD CUTTER FOR SEWING MACHINES. APPLICATION FILED APR.24. 19u.

.1,3 32,5 1 2, Patented Mar. 2, 1920.

4 SHEETS-SHEET l.

1. Ia, Morm AND a. s. mso. THREAD CUTTER FOR SEWING MACHINES.

APPLICATION FILED APR, 24. 1947. l 1,3325 12, Patented Mar. 2, w20,

' 4 SHEETSTSHEET 2.

J. R. MOFFATT AND R. S. KELSO. THREAD CUTTER FIOR SEWING MACHINES APPLlcATloN` FILED AFB. 24,1917.

1,332,5 1 2. Patented Mar. 2, ma

4 SHEETS-SHEET 3.

fitbozwwS L R. MOFFATT AND R. S. KELSO. THREAD CUTTER Foa SEWING MACHINES. APPLICATION FILED APFL24. l9l7.

Patented Mar. 2, E920.

4 SHEETS-SHEET 4.

tiled December 11th, 1916, et which the present application yis a division.

The machine is provided with a standard 1 carrying an overhanging arm 2' and a second projecting arm -3 at the outer end of which is mounted a .work support 4i. The material isheld on the work `support by a presser foot 5. Reciprocating in suitable bearings is a needle bar o carrying, as herein shown, two needles 7 and 8.. These needles are ot' the hook type and are provided with suitable sliding latches for closing the hooks, all oi which, together with the mechanism for operating the same, is fully set forth in the application referred to above.

The needle 7 is supplied with a needle thread 7a and the needle 8 is supplied with a needle thread 8a. These. needle threads pass through suitable tensions, indicated at l,

thence through guide eyes 9--9, respectively,

and thence through guiding eyes in a pullod arm 10. From the pull-ohe arm l0, the threads are led through a stationary thread guide 1l, and thence through thread guides 12 and 13 to the movable threading guides le. 'lhese threading guides operate to lay the threads, respectively, in the hooks of the needles when 'the hooks oit' said needles are above the material. The needle bar is reciprocated in the usual manner. After the threads have been laid in the hooks of the needles, said hooks moving beneath thematerial draw the loops down through the material. As the needles again rise, they pass up through the material, engaging the needle threads, and again 'form loops which having a cutting edge 16. The thread cutting blade l is carried by a lever 17 which is pivoted at 18 to the bearing bracket on the machine. Al link 19 is pivoted at 20 to said lever 17, and the other end of the link is pivoted 'to ana-rm 2l by a shaft 22. The shaft 22 on its outer end carries a second arm 23.

I'lhe take-up arm l0 is pivoted at 24 to a suitable bearing on the overhanging arm. A link 25 is connected to the outer end of this arm at 26. lhis linlr at its' upper end is pivoted 27 to a lever 28. The lever 28 is ulcrumed at 29 to the overhanging arrn. A rod 30 is connected at 31 to the lever 18, and the other end of this rod is connected through shitable devices either to a linee shift or a treadle so that the rod may be depressed at the will ot the operator. A

sprint)` 83 normally operates to hold the shaft 36 has a hub with a slot 37 formed radially therein. lli/'hen this slot 37 is in vertical position, as indicated in Fig. l, the rod 30 may be depressed andthe finger 34C will move into the radial slot. When, however, this slot is out of register with the finger, then any attempt to' depress the rod 30 will bring the end of the linger against the hub, as indicated in llig. 2, and prevent the manipulation oi' the lever 28.

rl`he' lever 28 carries a pin 88 which er;- tends into a slot 39 in the upper end of a rod 40, rThe lower end of this rod 4:0 ispivoted at 41 to the arm 23. When the rod 30 connected with the treadle is raised, the pin 38 is adjacent the upper end of the slot 39.

This slot aords a lost motion between the lever 28 and the rod Oi so as to permit the lever 28 to have a certain movement before the rod d() is moved and before the cutter will be operated.

When the machine stops with the needles clear down, the. recess 37 will be in line with the finger 34, and the operator may depress the treadle or operate the knee shift, swinging the lever 28 about its fulcrum. The first movement of the needle 28 results in pulling thread from the supply by the swinging of the arm' l0. "When the pin 3S reaches the end ot the slot 39, then the rod 40 will be forced downwardly, this `will move the shaft 22 in a counterclockwise direction, which will pullon the link 19 and swing the lever 17 so aste cause the cutter to move forward and engage one strand of the Yloop 'in the needle thread whichis held by the needle. When two needles are used, as shown in the drawings, the edge ot the cutting blade is positioned so as to simultaneously engage both needle loops.

From the a ove description, it will be apparent that we have provided a cutter .operating mechanism which can only `be operated when the needles are retracted and the thread properly positioned for cutting. Vile have also provided a thread pull-oil mechanism which is operated in advance of the actuation oi" the cutter which severs the threadsu @nly one strand ot the needle thread loop is cut, and this is the strand between the hook of the needle and the material. After this strand is out, when the material is pulled from the machine the split end of the thread extends through the material and around the hoolr, and the pull' ing' of the thread out ot the machine through the friction ofthe material, on the thread draws the slack pulled ofi through the 'thread eyes and the end ot' the thread well out from underneath the presser toot. Whenel 2 the material is again inserted 'for' the next stitching operation, the /end ot' the thread extends well out from underneath the presser Yloot and will with certainty be clamped by the edge ot the presser foot and inname tirmly held so that the thread laying device can lay the thread in the hook of the needle.

llt is obvious that minor changes in the details of construction and the arrangements of partsA may be made without departing from the spirit of this invention as set forth in theappended claims,

Having thus described the invention, what is claimed as new is l. lllhe combination of a worlr support, a hook needle, and devices cooperating therewith tor forming chain stitches, a thread cutter, manually operated means for operating the thread cutter to cut one strand only of the thread loop on the` needle when the needle is retract/ed, and means for preventing the operation of said manually operated means except when the needle is retracted and out of the path of the thread cutter.

2. rlhe combination of a work support, a plurality of hook needles, devices coperating` therewith for independently forming chain stitches with each needle, a thread cutting blade having a cutting` edge parallel with a line passing through the needles whereby said cutting blade is adapted to simultaneously engage one strand only of each needle loop and sever the same, and manually controlled means for operating said cutting blade.

3. The combination of a work support, a plurality of hook needles, devices coperating therewith for independently forming chain stitches with each needle, a thread cutting blade having,r -a cutting edge parallel with a line passing through the needles whereby said cutting blade is adapted to simultaneously engage one strand only of each needle loop and sever the same, manually controlled means for operating said cutting' blade, and means t'or preventmg the operation olf' said manually controlled means except when the needles are fully retracted and out or the path of said cutting blade.

4. rlihe combination of a work support, ya hoolr needle mounted beneath the work support, a device above the work support cop- .eratingl with said hook needle for laying a thread therein, a thread pull-ott arm fior the needle thread located above the work support, a thread cutting; mechanism for cut- "ti-ngin 'the needle thread located beneath the work support, manually operated means for actuatingg the thread cutter to out one strand only ot the thread loop on the needle when the needle is retracted, said manually controlled means includingdevices whereby the thread pull-od arm will be operated to pull olf thread in advance of the cutting of the thread loop.

l5. rlhe combination of a work support, of

a hook needle located beneath the work sup-v port and adapted to move through the material to engage the needle thread for forming a loop therein, a thread pull-od' located port and adapted to move through the material to engage the needle thread for torming'. a loop therein, a thread pull-ofi" located above the work support through which the needle thread passes, a thread cutter located beneath the work support and adapted to dut one strand only of the needle thread loop on the lneedle when the needle is retracted, and manually controlled means for operating said pull-oil and said thread cutter, said manually controlled means includingdevices whereby the thread pull-off is operated in advance of the thread cutter.

7. The combination of a work support, of a hook needle located beneath the work support and adapted to move through the material to engage the needle thread for forming'a loop therein, a thread pull-oil located above the lwork support through which the needle thread passes, a thread cutter located beneath the work support and adapted to :.cut one strand only of the needle thread loop on the needle'when lthe needle is retracted, manually controlled means .tor operating .said pull-od and said thread cutter, said manually controlled means including devices whereby the thread pull-on is operated in advance of the thread cutter, and means for preventing the operation of the manually controlled means except when the needle is fully retracted and out oit 'the path or the cutter.

ln testimony whereof, we am); our signatures, in the presence of two witnesses.

JAMES R. MFFATT. RALPH S. EELS@ l/Vitnesses:

S. Grenen Tarn, S'rnnirun Tetonas. 

